Register Number
SATHYABAMA UNIVERSITY
(Established under section 3 of UGC Act,1956)
Course & Branch :B.Tech – CHEM
Max. Marks:80
Title of the Paper :Chemical Engineering Thermodynamics-I
Sub. Code :SCHX1002 (2010-11)
Time : 3 Hours
Date :01/11/2012
Session :FN
_______________________________________________________________________________________________________________________________
1.
PART - A
Answer ALL the Questions
Differentiate Work and Heat.
2.
Define irreversible process.
3.
What are the limitations of first law of thermodynamics?
4.
State Kelvin-Planck statement.
5.
What is an equation of state?
6.
Define Acentric factor.
7.
Show that for an ideal gas Cp-Cv = R from basic principles.
8.
Define Joule Thomson Coefficient.
9.
Why the inter cooling is necessary in a multi stage compressor?
10. What is compressibility ratio?
(10 x 2 = 20)
PART – B
Answer ALL the Questions
(5 x 12 = 60)
11. List out difference between Point function and Path function with
examples.
(or)
12. Define reversible and irreversible process with examples.
13. Develop the first law of thermodynamics for a steady state flow
process.
(or)
14. (a) Air at 1 bar and 25°C enters a compressor at low velocity
discharges at 3 bar and enters a nozzle in which I expands to final
velocity of 600 m/s at the initial condition of pressure and
temperature. If work of compression is 240 kJ/kg of air, how
much heat must be removed during compression?
(b) Oil at 500 K is to be cooled at rate of 5000 kg/hr in an
exchanger using cold water available at 295 K. Temperature
approach of 10 K is to be maintained at both ends of the
exchanger. Specific heat of oil and water is 3.2 and 4.2 kJ/kg K
respectively. Determine total entropy change in the process.
15. Prove that the Vander Waal’s constants
27 R 2TC 2
a
64 PC
and
b
RTC
8PC
from fundamental principle.
(or)
16. Determine molar volume of n-butane at 510 K and 25 barby each
of the following
(a) Ideal gas equation
(2)
(b) The generalized compressibility factor correlation
(5)
(c) The generalized Virial –coefficient correlation
(5)
Data: PC = 37.96 bar, TC = 425.1 K, at Pr = 0.659 and Tr = 1.2,
Z0=0.865, Z1=0.038 and ω =0.2
17. Derive the following
 2TV
(a)
C P  CV 
(b)
C P  CV  R
(10)
K
for an ideal gas
(or)
18. Show that
(a) dH  C P dT  (1  T )VdP
(2)
(b)

dU  CV dT  ( T  1)dV
k
19. Show that in multi stage compressor operation, the condition for
minimum work is P  P P , when the work in all stages is the
same, provided that the gas is cooled to the initial temperature
each stage. Where P2 is intermediate preesure.
(or)
20. A two stage air compressor with ideal intercooler compresses 5
m3/min of free air from 1 bar to 16 bar pressure. The clearance
volume in LP cylinder is 4% of its stroke volume. Mechanical
efficiency of compression is 80%. Assume compression and
expansion follows the law PV1.3= constant. Calculate
(a) Work for the compressor
(b) Clearance volumetric efficiency in LP cylinder
Actual works increase if the air compressed in single stage
compressor with same pressure.
2
1 3